The device will need to be compared with the latest generation of flow diverters, one expert points out.
The Surpass flow diverter (Stryker Neurovascular) continues to demonstrate excellent efficacy and safety outcomes at 1 year after the treatment of giant, wide-neck aneurysms occurring in the internal carotid artery, the latest follow-up the SCENT trial shows. The results were published online May 14, 2019, ahead of print in Stroke.
SCENT is “the largest trial to date with adjudicated data on the use of flow diverters,” lead author Philip M. Meyers, MD (Columbia University Irving Medical Center, New York, NY), told Neurovascular Exchange in a telephone interview.
“The SCENT trial has extended the indications for the use of flow diverters from a narrower indication to a broader one, including the entire intracranial internal carotid artery,” Meyers said. “Previously, on-label use of flow diversion in the United States had been limited to a segment of the internal carotid artery extending from the petrous to ophthalmic. With the new design of the Surpass device, however, the range of eligible aneurysms was increased in SCENT to include not only petrous to ophthalmic segments but also the entire supraclinoid internal carotid artery to its terminus. This includes the more challenging posterior communicating and choroidal segments as well.”
For the multicenter, prospective, single-arm SCENT trial, 180 patients with 180 target aneurysms were enrolled in a modified intention-to-treat cohort. Target aneurysms had all undergone failed treatment and were located anywhere in the intracranial internal carotid artery, extending from the petrous segment to the carotid terminus at its bifurcation into the anterior and middle cerebral arteries. In addition, target aneurysms were all wide-neck (≥ 4 mm) and large or giant size (≥ 10 mm).
The results of SCENT were compared with performance goals derived from the medical literature, with a primary effectiveness endpoint involving three components: 1) complete aneurysm occlusion, 2) absence of significant parent artery stenosis (≥ 50%), and 3) no retreatment at 12 months. The primary safety endpoint was major ipsilateral stroke (increase in NIHSS score of ≥ 4) or neurological death within 12 months.
Angiographic core lab assessment revealed that 8.3% of target aneurysms were fusiform, 91.1% saccular, and 0.6% blister. Mean aneurysm size was 12.0 mm. Overall, 7.4% of the aneurysms were giant (≥ 25 mm) and 32.2% were located in the supraclinoid and distal (including posterior communicating artery) segments of the internal carotid artery.
Mean procedure duration was 53.6 minutes. The device was successfully implanted in 97.8% of patients, with a mean of 1.1 devices per patient. SCENT met both primary safety and effectiveness endpoints, with a 12-month primary effectiveness rate of 62.8% and a 12-month major ipsilateral stroke or neurological death rate of 8.3%.
Meyers acknowledged the importance of real-world outcomes. Nevertheless, he said, “SCENT includes the largest adjudicated data set in the context of a multicenter trial in the United States and Europe. Physicians can use these data when they counsel patients about aneurysm treatment and the use of flow diversion. These conversations can be imprecise, and physicians should always relate their own personal experience to their patients. However, here in SCENT are some real quantitative data physicians can share with patients who may have aneurysms similar to those treated in the trial.”
Another important feature of SCENT, said Meyers, was that the Surpass device met or exceeded historical standards for safety and efficacy. Moreover, SCENT provides clinical data about flow diversion across the ophthalmic artery, adjudicated by ophthalmologists. Again, “Surpass remained safe and effective,” he said.
Needs Comparison With Latest Devices
In a comment on the study for NVX, Laurent Pierot, MD, PhD (Maison-Blanche Hospital, Reims, France), pointed out that the trial results “are exclusively compared with those of a first-generation [Pipeline] flow diverter and show that Surpass has a similar safety and efficacy.” Moving forward, he said, it will be important to compare it to the newest generation of flow diverters, including the FRED/FRED Jr (MicroVention) and p64/p48 (Phenox).
“Comparing these new devices with Surpass and Pipeline is important to determine if they all have a similar safety and efficacy, which will certainly affect clinical practice,” he said.
Pierot also noted some other important unanswered questions. “The antiplatelet treatment protocol in [the] SCENT trial was based on the use of aspirin and clopidogrel,” he noted. “It is well known that a high percentage of patients have resistance to clopidogrel, and current antiplatelet protocols for flow diversion use prasugrel or ticagrelor.” In addition, he said, “the future of flow diversion is the development of coated devices that will allow the use of single antiplatelet therapy (preferably aspirin).”
Meyers PM, Coon AL, Kan PT, et al. Stroke. 2019;Epub ahead of print.
- Meyers reports being a primary investigator in the SCENT trial and a consultant to Stryker Neurovascular.
- Pierot reports being a consultant to Balt, MicroVention, and Phenox.